It is common practice to construct condominiums and apartment buildings which comprise many individual units with central heating and/or cooling systems which supply hot and/or cold water or air to a number of units therein, or all of them. If the heating/cooling costs are allocated on a fixed basis there is little incentive for each tenant or owner to economize his energy use. Evidence exists, however, that aggregate energy consumption is reduced as much as 23% when each user is billed separately for the energy he consumes.
Prior to my invention to be described hereinafter, systems which permit allocation of energy cost to users on the basis of their energy usage were relatively expensive. They required at the least a flow meter for heating/cooling fluid at each unit. This requirement complicates plumbing, increases considerably the heating/cooling system first cost, as well as maintenance charges, and requires that each meter be read at regular intervals. It is the principal object of my invention to provide an energy use monitoring system free from those drawbacks.